Evolution (BIOL 473): Chapters 1 & 2

Vocabulary flashcards covering core terms, evidence for descent with modification, speciation, homologies, and geological dating methods from Chapter 1.

Scientific Law

States what happens, or is observed, every time something is observed.

Scientific Theory

An explanation for observations that is supported by all current evidence.

Evolution

The scientific theory explaining the change and appearance of species over time through the action of biochemical mechanisms and the environment (mutation & natural selection).

Descent with Modification

The process by which species change over time, as defined by Charles Darwin in 1859.

Speciation

The process by which new species arise from existing ones.

Artificial Selection (Selective Breeding)

Selecting parents with particular characteristics to breed together and produce offspring with more pronounced characteristics.

Vestigial Traits

Useless, or rudimentary, traits that are homologous to functional traits in closely related species.

Vermiform Appendix

A vestige of an organ used to digest cellulose by humans' herbivorous ancestors.

Coccyx

The tailbone in humans, which is the remnant of a lost tail.

Wisdom Teeth

Vestigial third molars that human ancestors used to help in grinding down plant tissue.

Plica Semilunaris

A small fold of tissue on the inside corner of the eye; the vestigial remnant of the third eyelid which is present in other animals such as birds, reptiles, and fish.

CMAH

CMP-N-acetylneuraminic acid hydroxylase, an enzyme disabled by a $92\text{-base-pair}$ deletion in humans that converts Neu5Ac into Neu5Gc.

GULO

Gulonolactone oxidase, an enzyme whose inactivation during evolution caused humans to lose the ability to synthesize vitamin C from glucose.

GULOP

Gulonolactone (L-) Oxidase Pseudogene; a vestigial nonfunctional human gene needed in the pathway that converts glucose to vitamin C.

Pseudogene

A nonfunctional segment of DNA that arises from a previously functional gene.

Species

Populations among which individuals actually, or potentially, interbreed and outside of which they do not interbreed.

Fossil

Any trace of an organism that lived in the past.

Fossil Record

The worldwide collection of fossils.

Law of Succession

The observation that fossil types are succeeded in the same geographic area by similar fossils or living species.

Transitional Forms

A species that exhibits traits common to ancestral and derived groups especially when the groups are sharply differentiated.

Comparative Anatomy

The study of trait structure and function by comparing anatomical structures across species.

Homology

Similarity between species that results from inheritance of traits from a common ancestor.

Ma

Mega annum, representing millions of years ago ($10^6\text{ years}$).

Ga

Giga annum, representing billions of years ago ($10^9\text{ years}$).

Analogous Structures

Features of different species that are similar in function but do not derive from a common ancestral feature.

Molecular Homology

Similarities between species on the molecular level.

Processed Pseudogenes

A pseudogene that originated when a messenger RNA (introns removed) was reverse-transcribed into DNA and inserted into the genome, leaving a gene with no introns and no promoter region nearby.

Retrotransposons

Transposable elements that move via an RNA intermediate and contain the coding sequence for reverse transcriptase.

Uniformitarianism

Geological processes identical to those at work today are responsible for events that occurred in the past.

Dendrochronology

Method of dating based on the analysis of patterns of tree rings and petrified wood.

Ice Core Dating

A dating method based on seasonal layers created in ice and dust to reconstruct past climate and date specific historical events.

Coral Laminations Dating

A dating method utilizing seasonal layers added by corals to their calcium carbonate shells.

Micropaleontology

The study of microscopic fossils.

Speleothem Dating

A dating method where cave rocks form annual bands that can be used for dating and telling the amount of rainfall.

Varves

Alternating layers of sediment of contrasting color and texture that represent the deposits of a single year (summer and winter), particularly in lakes.

Magnetostratigraphy

Dating rock by looking at the orientation of its magnetization, which is determined by the polarity of Earth's magnetic field at the time a stratum was formed.

Radiometric Dating

Dating materials by comparing the amount of a radioactive isotope and its decay products, using known decay rates.

Thermoluminescence Dating

An absolute dating method involving heating a rock until it emits light, then measuring the amount of radioactivity accumulated by the rock since it formed.

Optical Dating

A dating method using a very bright source of light that causes a rock to emit ultraviolet light revealing the amount of radioactivity accumulated by the rock since it formed.